devicetree: bindings: Document qcom,kpss-acc

The kpss acc binding describes the clock, reset, and power domain
controller for a Krait CPU.

Cc: <devicetree@vger.kernel.org>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NKumar Gala <galak@codeaurora.org>

Documentation/devicetree/bindings/arm/msm/qcom,kpss-acc.txt

+Krait Processor Sub-system (KPSS) Application Clock Controller (ACC)
+
+The KPSS ACC provides clock, power domain, and reset control to a Krait CPU.
+There is one ACC register region per CPU within the KPSS remapped region as
+well as an alias register region that remaps accesses to the ACC associated
+with the CPU accessing the region.
+
+PROPERTIES
+
+- compatible:
+	Usage: required
+	Value type: <string>
+	Definition: should be one of:
+			"qcom,kpss-acc-v1"
+			"qcom,kpss-acc-v2"
+
+- reg:
+	Usage: required
+	Value type: <prop-encoded-array>
+	Definition: the first element specifies the base address and size of
+		    the register region. An optional second element specifies
+		    the base address and size of the alias register region.
+
+Example:
+
+	clock-controller@2088000 {
+		compatible = "qcom,kpss-acc-v2";
+		reg = <0x02088000 0x1000>,
+		      <0x02008000 0x1000>;
+	};